Electrophotographic recording material containing photoconductive porphyrin compounds

Abstract

An electrophotographic recording material comprising a conductive support and a photosensitive layer containing at least one photoconductive compound that has p-type charge generating capacity and is a tetrabenzoporphyrin type compound represented by the following general formula (I): ##STR1## wherein: each of X 1 , X 2 , X 3 , and X 4 (same or different) represents a substituent selected from the group consisting of halogen, e.g. chlorine or bromine, nitro, cyano, (C 1 -C 2 ) alkyl and alkoxy, e.g. methoxy or ethoxy or 2 X 1 's, 2 X 2 's, 2 X 3 's or 2 X 4 's together represent the atoms necessary to form a substituted or unsubstituted carbocyclic or heterocyclic ring system; k, l, m, and n each and independently represent zero or an integer 1 to 4, R 1 represents hydrogen, a (C 1 -C 2 ) alkyl, aralkyl or aryl group; each of the A's (same or different) represents nitrogen, or a CR 2 group, wherein each of the R 2 's (same or different) represents hydrogen, a (C 1 -C 2 ) alkyl, aralkyl or aryl group; and Z is hydrogen or two groups Z together stand for a metal atom which in the case of higher valency state than 2, will be linked to (an) additional valency compensating atom(s) or group.

I claim: 
     
       1. An electrophotographic recording material comprising a conductive support and a photosensitive layer containing at least one photoconductive compound that has p-type charge generating capacity and is a tetrabenzoporphyrin type compound represented by the following general formula (I): ##STR25## wherein: each of X 1 , X 2 , X 3 , and X 4  (same or different) represents a substituent selected From the group consisting of halogen, nitro, cyano, (C 1  -C 2 ) alkyl and alkoxy or 2 X 1  's, 2 X 2  's, 2 X 3  's or 2 X 4  's together represent the atoms necessary to form a carbocyclic or heterocyclic ring system including such ring systems in substituted form; k, l, m, and n each and independently represent zero or an integer 1 to 4, R 1  represents hydrogen, a (C 1  -C 2 ) alkyl, aralkyl or aryl group; each of the A's (same or different) represents nitrogen, or a CR 2  group, wherein each of the R 2  's (same or different) represents hydrogen, a (C 1  -C 2 ) alkyl, aralkyl or aryl group; and Z is hydrogen or two groups Z together stand for a metal atom which in the case of higher valency state than 2, will be linked to (an) additional valency compensating atom(s) or group.   
     
     
       2. An electrophotographic recording material according to claim 1, wherein said photosensitive layer is a photosensitive charge generating layer that has in contiguous relationship thereto a charge transporting layer. 
     
     
       3. An electrophotographic recording material according to claim 2, wherein said photoconductive compound is applied in combination with a resin binder to form a charge generating layer adhering directly to a conductive support. 
     
     
       4. An electrophotographic recording material according to claim 3, wherein said photoconductive compound is selected from the group consisting of a cellulose ester, acrylate and methacrylate resins, polyvinyl chloride, copolymers of vinyl chloride, polyester resins, aromatic polycarbonate resins, silicon resins, polystyrene and copolymers of styrene and maleic anhydride, copolymers of butadiene and styrene, poly-N-vinylcarbazole and copolymers of N-vinylcarbazole having a N-vinylcarbazole content of at least 40% by weight. 
     
     
       5. An electrophotographic recording material according to claim 2 to 10, wherein the content of said photoconductive compounds in the charge generating layer is in the range 30 to 70% by weight with respect to the total weight of said layer. 
     
     
       6. An electrophotographic recording material according to claim 2, wherein the thickness of said charge generating layer is less than 5 μm. 
     
     
       7. An electrophotographic recording material according to claim 2, wherein the thickness of said charge transporting layer is in the range of 5 to 50 μm. 
     
     
       8. An electrophotographic recording material according to claim 2, wherein in the recording material an adhesive layer or barrier layer is present between the photosensitive layer or the charge transport layer and the support and the thickness of said barrier layer is not more than 1 micron. 
     
     
       9. An electrophotographic recording material according to claim 1, wherein said tetrabenzotriazaporphyrin is selected from the group consisting of ##STR26## 
     
     
       10. An electrophotographic recording material according to claim 1, wherein said photoconductive compound is metal-free tetrabenzotriazaporphyrin. 
     
     
       11. An electrophotographic recording material according to claim 1, wherein said photoconductive compound is metal-free tetrabenzotriazaporphyrin in the ω-crystalline modification characterized by its absorption spectrum shown in FIG. 1c herein and its X-ray diffraction pattern exhibiting strong lines at Bragg angles (2θ) of 8.5; 10.2; 11.9; 14.4; 18.0; 20.4; 22.6; 24.0; 24.7 and 29.8 degrees. 
     
     
       12. An electrophotographic recording material according to claim 1, wherein said photoconductive compound is metal-free tetrabenzotriazaporphyrin in the ω-crystalline modification which has been treated with hot methyl benzoate or hot xylene. 
     
     
       13. An electrophotographic recording material according to claim 1, wherein the content of said photoconductive compounds in the photosensitive layer is in the range of 0.05 to 90 by weight with respect to the total weight of said layer. 
     
     
       14. An electrophotographic recording material according to claim 1, wherein the thickness of said photosensitive layer is less than 30 um. 
     
     
       15. An electrophotographic recording material according to claim 1, wherein the conductive support is made of aluminium, steel, brass or paper or resin material incorporating or being coated with a conductivity enhancing substance, the support being in the form of a foil, web or being part of a drum.